1. Field of the Invention
The present invention relates to a hydraulic damping device, and more particularly to a lightweight hydraulic damping device which exhibits excellent durability when exposed to heat.
2. Description of Related Art
One example of a conventional hydraulic damping device is disclosed in U.S. Pat. No. 4,858,879. In this conventional device, as shown in FIG. 3, a metallic support member 12 is embedded in the axially central portion of a thick rubber elastic body 10 which has a hollow conical configuration and opens downward. The support member 12 is connected by a bolt 14 to a bracket 15 fixed to a vibrating body (not shown), such as an engine.
A cylindrical side plate 16 composed of a metallic plate is joined to an outer peripheral surface of the rubber elastic body 10. An opening defined by a lower end of the side plate 16 is closed with a partition member 18 to define a main liquid chamber 20 with the rubber elastic body 10. A thin rubber film 24 is provided under the partition member 18 to define an auxiliary liquid chamber 26 with the partition member 18. A restricted liquid passageway 22 is defined at an axial center of the partition member 18 for interconnecting the main liquid chamber 20 and the auxiliary liquid chamber 26.
A lower end edge of the side plate 16 is secured by caulking to an upper end edge of a cylindrical support member 28. A lower end edge of the support member 28 is connected by a bolt 30 to a vehicle frame 29.
An annular stopper member 31 is fixed to the support member 12 so as to be opposed to the upper half of the rubber elastic body 10 with a predetermined spacing. An annular cover 311 is attached to a peripheral edge of the stopper member 31 so as to surround the rubber elastic body 10.
Reference numeral 13 designates a ring member embedded within the rubber elastic body 10 for preventing buckling of the rubber elastic body 10, and 312 designates an annular pad member which is attached to the under surface of the stopper member 31 so as to be brought into contact with the peripheral surface of the rubber elastic body 10 above the ring member 13.
With the above-described example of the conventional device, by virtue of the cover 311, damage of the rubber elastic body 10 due to radiation heat or thermal effects by the engine can be prevented. However, the provision of the cover 311 results in an undesirable increase in the number of parts, and accordingly, an undesirable increase in the weight of the device.